It is also our intention to illustrate that perverse sheaves are a powerful tool in the study of
singular mappings. For the reader who is unfamiliar with the machinery of
perverse sheaves, [1]} provides a quick introduction. Here we have
included only the information that is necessary for our applications,
and have avoided technical definitions. For those who are already
well-versed in the topic, some non-trivially perverse sheaves related to
the alternating cohomology of multiple points are introduced in Section
. The perversity of these sheaves was discovered by
Houston [2]} .
